Fuels for internal combustion piston engines and to the operation of such engines



United States Patent 3,131,67 7 FUELS FOR ltNTERNAL CQMBUSTION PISTONENGINES AND TO THE ()PERATION OF SUCH ENGINES Horace John Eatwell andStanley Thomas Walker, Sunhury-on-Tharnes, England, assignors to TheBritish Petroleum Company Limited, London, England, a jointstockcorporation of Great Britain No Drawing. Filed Jan. 13, 1960, Ser. No.2,117 Claims priority, application Great Britain Jan. 14, 1959 9 Claims.(Cl. 123-1) The running-in of internal combustion piston engines hasalways presented a problem. In the case of gasoline engines and smalldiesel engines such as are used in road vehicles, no satisfactory methodhas been developed for running in the engine quickly and, because of thetime that it takes to run the engine in under normal operatingconditions, it is not usually economically practicable for the engine orvehicle manufacturers to run the engine in before the vehicle leaves thefactory Where it is manufactured.

While the engine is being run in it is important that its speed be keptbelow a certain value and the running-in of the engine should becontinued until the oil consumption reduces to a steady level which maybe in excess of 10 hours. Failure to observe these precautions is likelyto result in serious damage to the engine particularly to the pistonrings and cylinder walls.

In the case of larger diesel engines, i.e. medium and slow-speed dieselengines, it is customary to run the engine in before it goes into normalservice. The only commercially used accelerated running-in procedure forsuch engines involves the use of a naturally occurring volcanic ashwhich is fed into the engine cylinder with the air supply and which actsas an abrasive and so causes rapid wearing of high spots on the pistonrings and cylinder. This procedure however suffers from a number of.drawbacks. For example, the quantity and consistency of the materialbeing supplied to the cylinder has to be carefully controlled otherwiseserious damage may occur; it is not always possible to use the procedurein multicylinder engines.

It has now been found that the running-in of piston engines can bequickly and effectively carried out by running the engine for a shorttime on a fuel containing a particular additive.

According to the invention, a fuel composition suitable for use inrunning-in an internal combustion piston engine, consists essentially ofa fuel suitable for operating such an engine, e.g. a gasoline or adiesel fuel, and having dissolved therein a minor amount, preferablyO.l%, e.g. 0.25 %-2.5%, by weight, of an oil-soluble aluminium compoundwhich can be converted to the oxide by heating. The term oil-soluble isused in the sense that the compound must be capable of remaining instable suspension in the fuel and not separate out on storage. Thus thecompound may be present in the fuel in the form of a colloidalsuspension.

A preferred class of aluminium compounds are polymeric organic aluminiumcompounds of the general formula O Al X where X is an acylate group(i.e. a group having the formula RCOO-where R is an aliphatic oraromatic hydrocarbon or substituted hydrocarbon radi- 3,131,677 PatentedMay 5, 1964 ICC cal), m, n, and p are integers, m is not less than 2,m/n is 0.75-2.0 and m/ p is 0.5-3.0. It is to be understood that theacylate groups in any given molecule of the additive may be the same ordifferent.

Preferred additives are those of the formula (OAIX) where q is aninteger greater than one, preferably 2-10, especially 3. The acylategroups are preferably those of the formfula RCOO-where R is a saturatedor unsaturated alkyl or aryl radical containing 6-30 carbon atoms.Particularly preferred are the acylate groups derived from benzoic orsalicylic acids, or aliphatic monocarboxylic acids having 12-20 carbonatoms, e.g. stearic or oleic.

ne polymeric organic aluminium compounds referred to above are commonlydescribed as polyoxo-aluminium acylates. They may be prepared by heatingaluminium alcoholates with water and carboxylic acids in one or morestages and preferably in an inert, non-volatile diluent such as a lightlubricating oil. This method of preparation is described in thespecification of U.K. Patent Specification 825,878. Alternatively, theymay be prepared by heating aluminium alcoholates with carboxylic acidsalone so as to liberate alcohol and form acyloxy aluminium alcoholatecompounds, and further heating the latter compounds. This method ofpreparation is described in the U.K. Patent Specification 806,113.

Certain of the aluminium additives are available commercially under thetrade name Manalox. One such commercially available material(hereinafter called additive M) is believed to consist of a solution inone part by weight of iso-propyl oleate of one part by weight of amaterial of the formula (OAlOCR where R is an oleyl radical. It wasprepared as follows: One molecular proportion of aluminium isopropoxidewas reacted with two molecular proportions of commercial oleic acid at atemperature increasing to about 220 C. Two

molecular proportions of isopropanol distilled ofi during the reaction,a slight vacuum being applied near the end of the reaction to aid theremoval of the last traces of isopropanol.

Another class of oil-soluble aluminium compounds which are suitable foruse in the fuel compositions according to the invention are aluminiumglycolates.

The invention also consists in a method of running-in an internalcombustion piston engine which comprises running the engine on a fuel ashereinbefore specified, preferably until the oil consumption of theengine has fallen to a substantially steady level.

A number of examples of the invention will now be described.

Example 1 A single cylinder 550 cc., gasoline engine, fitted with aradioactive piston ring, was run on a commercial grade motor gasoline(boiling range 42.5 to 164 C.) containing 2% by weight of additive M.The engine was operated at 1500 rpm. which is considered to be a goodnormal running-in speed for such an engine. The wear of the piston rings(as measured by the radioactive tracer technique) took place at a steadystate which was 2000 times the wear rate when running the engine underidentical conditions with the same gasoline not containing the additiveM. This result indicates the the use of the additive M in the fuel wouldaccelerate the running-in of a gasoline engine very considerably.

Example 2 Fuel D1:A commercial diesel fuel of boiling range 195 to 351C.

Fuel D2:Fuel D1 containing 1% wt. additive M.

Fuel D31Fuel D1 containing 0.5% wt. additive M.

The wear rate of the piston rings when using Fuel D2 was up to 50 timesand, when using Fuel D3, up to 25 times the wear rate when using FuelD1.

The amount of piston ring wear when operating the engine for a period of2 hours on Fuel D2 was equivalent to the amount known to be necessaryfor satisfactory running-in of the engine in the normal way using a fuelsuch as D1; normal running-in usually takes about 50 hours. It cantherefore be deduced that the use of 1% wt. of the additive M in thefuel reduces the running-in period of the engine from 50 hours to 2hours.

Example 3 A 550 cc., single cylinder, trunk piston, medium speed dieselengine fitted with a new liner, piston and ring assembly was run at 1500r.p.m. for 2 hours using a commercial diesel fuel of boiling range 195to 351 C. and containing 1% wt. of additive M.

At the end of this running time the oil consumption was similar to thatafter about 50 hours running-in with the untreated fuel. From this itcan be deduced that the use of 1% wt. of the additive M in the fuelreduces the running-in period of the engine from 50 hours to 2 hours.

Example 4 A 1400 cc., single cylinder trunk piston, medium speed dieselengine fitted with a rehoned liner and a new piston and ring assemblywas run at gradually increasing loads and speeds up to the maximum ratedoutput of the engine (16 brake horse power at 1500 r.p.m.) for 2 hoursusing a commercial diesel fuel of boiling range 195 to 351 C. andcontaining 0.5% wt. of additive M.

At the end of this rtmning time the oil consumption was similar to thatobtained after a six-hour run-in using conventional methods.

Example 5 A 3400 cc., single cylinder, trunk piston, medium speed dieselengine of the type used in large earth moving equipment, and fitted witha new liner, piston and ring assembly was run at gradually increasingloads and speed up to 20 brake horse power 'at 1000 r.p.m. for 2 hoursusing a commercial diesel fuel (boiling range 195 to 351 C.) andcontaining 2% wt. of additive M.

At the end of this running time the oil consumption was less than thatobtained by using an abrasive powder to accelerate the run-in. It isnormal practice in this particular engine to use a specified abrasivepowder during the run-in period, because by merely running the engine itcan take up to 500 hours before a satisfactory stable low oilconsumption is obtained.

Example 6 A 250 cc., single cylinder, trunk piston, high speed gasolineengine fitted with a new liner, piston and ring assembly was run atgradually increasing speeds and loads up to 2500 r.p.m. and 46 brakehorse power for 2 hours using a commercial gasoline (boiling range 42.5to 146 C.) containing 0.5% wt. of additive M.

At the end of this running time the oil consumption was one half of thatobtained after a normal 8 hour run-in period.

Example 7 The engine used in Example 6 was run under the sameconditions, but the gasoline contained 2% additive M.

At the end of this running time oil consumption was one fifth of thatobtained after a normal 8 hour run-in period.

by wt. of

Example 8 A 2180 cc., four cylinder, trunk piston, high speed gasolineengine fitted with rehoned liners, new pistons and ring assemblies wasrun at gradually increasing speeds and loads up to 3500 r.p.m. and 60brake horse power for 2 hours using a commercial gasoline (boiling range34 to 186 C.) containing 0.5% wt. of additive M.

At the end of this running time the oil consumption was similar to thatobtained after a normal 8 hour run-in period.

It will be appreciated that the short time that it takes to run in anengine when using the fuel or method according to the invention makes itvery much easier and more economically feasible for engine and vehiclemanufacturers to run-in engines before delivery of the engines orvehicles.

The effect of using the polymeric organic aluminium additives abovespecified in fuels for internal combustion piston engines is verysurprising because the same additives when used in lubricatingcompositions for the cylinders of diesel engines operating onhigh-sulphur fuels are very eifective in reducing the high cylinder wearrate normally associated with the use of such fuels. It is believed thatthe effect of using the additives in fuels is due to the fact that underthe conditions prevailing during the combustion of the fuel in theengine cylinders the aluminium compounds break down into a highlyabrasive form of aluminium oxide.

We claim:

1. A fuel composition suitable for use in running-in an internalcombustion piston engine, said composition consisting essentially of afuel suitable for operating an internal combustion piston engine andsaid fuel being selected from the group consisting of gasoline enginefuels and diesel fuels and having dissolved therein 0.l5%,

by weight of the composition, an oil-soluble aluminium compound whichmay be converted to the oxide by heating, said compound being apolymeric organic aluminium compound of the general formula (OAlX) whereq is an integer from 2-10 and X is an acylate group having the formulaRCOO, Where R is a substance selected from the group consisting ofaliphatic hydrocarbons, aromatic hydrocarbons and substitutedhydrocarbon radicals.

2. A fuel composition according to claim 1, in which the amount of saidaluminium compound is 0.252.5%, by weight of the composition.

3. A fuel composition according to claim 1, in which q is 3.

4. A fuel composition according to claim 1, in which the acylate groupsin said aluminium compound have the formula RCOO, where R is a radicalselected from the group consisting of alkyl and aryl radicals having6-30 carbon atoms.

5. A fuel composition according to claim 4, in which said acylate groupsare derived from at least one monocarboxylic acid selected from thegroup consisting of benzoic, salicyclic, and aliphatic monocarboxylicacids having 12-20 carbon atoms.

6. A fuel composition according to claim 5, in which said aliphaticmonocarboxylic acids are stearic and oleic acids.

7. A fuel composition according to claim 6, in which the said aluminiumcompound has the formula (OAlX) where X is an acylate group derived fromoleic acid, the amount of said aluminium compound in said fuelcomposition being 0.252.5% by weight of said composition.

8. A method of running-in an internal combustion engine which comprisesrunning the engine on a fuel composition according to claim 1.

5 6 9. A method according to claim 8, in which the engine 2,744,074Theobald May 1, 1956 is run until the oil consumption of said engine hasfallen 2,851,417 Andress Sept. 9, 1958 to a substantially steady level.2,902,983 Patberg Sept. 8, 1959 References Cited in the file of thispatent 5 5 9 FOREIGN PATENTS N 26 1931 3 ,494 Germany 0v. UNITED STATESPATENTS 1,076,375 France Apr. 21, 1954 3323 33 3 :32; 795,658 GreatBritain May 2 8, 1958 yons e 2,546,421 Bartholomew et a1 Mar. 27, 195110 OTHER REFERENCES 2,575,003 Caron et a1 Nov. 13, 1951 The CondensedChemical Dictionary, fifth edition, 2,739,049 Massa et a1 Mar. 20, 1956Reinhold Pub. Co., 1956, page 52.

Patent No. 3,, 131,677

May 5, 1964 Horace John Eatwell et a1.

It is hereby certified that ent requiring corr corrected below.

error appears in the above numberedzpatectio'n and that the sa idLetters Patent should read .as

Column 2 line 8, for "formfula" read formula line 31 for "(OAIOCR Signedand sealed this 22nd day of September- 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attcsting Officer Commissioner ofPatents

1. A FUEL COMPOSITION SUITABLE FOR USE IN RUNNING-IN AN INTERNALCOMBUSTION PISTON ENGINE AND SAID FUEL BEING SELECTED FROM THE GROUPCONSISTING OF GASOLINE ENGINE FUELS AND DIESEL FUELS AND HAVINGDISSOLVED THEREIN 0.1-5%, BY WEIGHT OF THE COMPOSITION, AN OIL-SOLUBLEALUMINUM COMPOUND WHICH MAY BE CONVERTED TO THE OXIDE BY HEATING, SAIDCOMPOUND BEING A POLYMERIC ORGANIC ALUMINUM COMPOUND OF THE GENERALFORMULA (OAIX)Q, WHERE Q IS AN INTEGER FROM 2-10 AND X IS AN ACYLATEGROUP HAVING THE FORMULA RCOO-, WHERE R IS A SUBSTANCE SELECTED FROM THEGROUP CONSISTING OF ALIPHATIC HYDROCARBON, AROMATIC HYDROCARBONS ANDSUBSTITUTED HYDROCARBON RADICALS.